Micro and nanostructured surfaces have broad applications ranging from liquid transport in microfluidics, cell manipulation in biological systems, to light tuning in optical applications. While significant efforts have focused on fabricating various static micro and nanostructures with asymmetric features, dynamically tunable structures may extend manipulation capability in these systems. For example, pH/temperature-sensitive hydrogels that contract or swell in response to a stimulus have been used to deform microstructures and serve as an ‘on/off’ switch for chemical reactions. However, this approach is limited because hydrogels generally need a liquid environment for actuation. On the other hand, magnetic manipulation is particularly attractive due to the non-intrusive nature of magnetic fields. For example, PDMS micropillars containing cobalt nanoparticles embedded in the PDMS matrix have been used to apply forces to living cells, leading to different cellular reactions. However, the low loading of magnetic particles in the polymer matrix produces low magnetic strength, and the micropillar deflection is non-uniform. Due to the difficulty in fabrication, uniform arrays with well-controlled dynamic tunability have not yet been demonstrated, which dynamic tunability would offer additional manipulation capability in these various systems.